Análise antropogeomorfológica da bacia hidrográfica do Mauazinho (Manaus/AM)

Abstract

Antropogeomorphology studies in the geographic science1s field, in the city of Manaus are still incipient, denoting the importance of using this line of research in environmental studies in urban areas. The research in question had as main objective to analyze the transformations of the physical environment, due to the anthropic actions, happened in the area of the Mauazinho Watershed (BHM), located in the eastern zone of the city of Manaus, Amazonas . To achieve this objective, the description was made of the changes in the natural environment intensified by the human occupation process within the basin; mapping of erosion risks; and the characterization of areas subject to gully erosion. The general characterization of the BHM was based on the identification Manaus city: local geology (Geological and Structural Formation); subdivision of the relief region, hydrography, soil types, climate and vegetation, ending with the human aspects of the occupation context and population data. The methodology is based on the geosystemic approach, began a bibliographical review on the topics addressed throughout the research. Afterwards, fieldwork was carried out to collect primary data, followed by the systematization of these data. The results of the research contemplate the physical characterization of the relief by determining parameters such as: the slope index that indicated the following percentages for relief classes: flat relief with 39% and smooth / wavy with 24.03%; the forms of terrain of the divergent-convex type corresponding to 14.09%; the hypsometry of the basin showed that it has an altimetric amplitude of 56 meters; most of the slopes are oriented toward the northwest with 18.90%; As for the general geomorphology of the basin, there are three forms of relief: plateau, slope and bottom of valleys; the basin relief patterns indicate that it has well defined valleys with slopes that have high slope indices varying from 20 to 45%. The study of the changes in the basin over the years indicates a significant increase of the urban areas corresponding to 48.51% of the total area of the basin. From the urbanization process, it was possible to identify occupancy patterns associated with relief forms: occupation in Plateau, slope and valley bottoms and the use of real estate: the majority corresponds to residential properties with 2,404 dwellings and 2,415 buildings do not have to register. Four types of erosion risk areas were identified: R1 (low), R2 (medium), R3 (high) and R4 (very high), where 39% of the basin area is in R4 and 40% of the properties are in this sector. The results of the research support the understanding of the dynamics of relief that directly contribute to the generation of these risk areas. Therefore, BHM presents a high probability of occurrence of events that may cause socioeconomic damages to the resident population, especially in the very high-risk sectors.